The basic concept of spinning fibers is centuries old. Spinning staple fibers into useful threads and yarns improved their overall strength, to a limited extent, and allowed the final yarn to be spun with varying degrees of thickness, strength, etc.
With the advent of synthetic textile fibers, the possibility arose for producing continuous filament yarns with greater strength and more durability than those from staple fibers, and also no shrinkage. Accordingly, it has become possible to produce knitted and woven fabrics for apparel, home furnishing and industrial use. The shrinkage of these fabrics can be controlled by using a yarn where the heat annealing point of the polyester fiber which is spun into the continuous filament state has been exceeded. Products made from polyester yarn have excellent strength properties, dimensional stability and good color fastness to washing, dry cleaning and light exposure. The use of 100% polyester knit and woven fabrics became extremely popular during the late 1960's and through the 1970's. More recently, continuous filament polyester fiber has also been cut into staple where it can be spun into 100% polyester staple yarns or blended with cotton or other natural fibers. However, both 100% polyester and polyester blended yarns and fabric made from these yarns have a shiny anti synthetic appearance, are clammy and prone to static conditions in low humidity, and tend to be hot and sticky in high humidity conditions. Additionally, polyester fiber, because of its high tensile strength, is prone to pilling in staple form and picking in continuous filament form.
Conventional methods of blending cotton and synthetics together have been less than fully successful as both mechanical and intermittent blends of polyester and cotton tend to pill, pick, shrink and are uncomfortable to wear. The consumer's use of polyester and polyester blended fabrics has been reduced over recent years in favor of 100% cotton fabrics which offer good appearance and comfort. This is especially true in the apparel industry. However, the use of 100% cotton yarn and fabrics also has its disadvantages. Primarily, fabrics made of 100% natural cotton tend to shrink and wrinkle. The most popular method of controlling cotton shrinkage for apparel outerwear is to coat the cotton fabric with resins made with formaldehyde. However, formaldehyde is considered to be a hazardous chemical and is therefore dangerous to handle during processing and is also considered dangerous on any fabrics that come into contact with the body because formaldehyde is a known carcinogen. Additionally, formaldehyde-based resins, when used to control the shrinkage of cotton or cotton blend fabrics, degrade the abrasion resistance and strength properties of the fabric, thus making them more prone to fabric holes, tearing and scuffing.
The use of prewashing to control shrinkage is also less than satisfactory because it is wasteful in terms of the energy consumed and it also gives garments a worn appearance. Mechanical compaction has also been used to control the shrinkage of cotton fabrics. However, this process is expensive because of the high working loss and it is also not a permanent solution as compacted garments tend to return to their pre-compacted dimensions. For these reasons, the treating of cotton by resin is the currently preferred method to control the shrinkage of cotton fabrics. However, because most resins contain formaldehyde, the fabrics treated with resin are unsafe both during the manufacturing process and during their use by the consumer.
Accordingly, there was a need in the art to produce yarns that have both the positive qualities of cotton fibers and synthetic filaments while eliminating their respective negative qualities. Applicant's commonly owned U.S. Pat. No. 5,383,331 and co-pending application Ser. No. 08/354,279 filed on Dec. 12, 1994 are each directed towards a composite yarn and a process for producing a composite yarn that comprises a filament yarn which is stretched to a second thickness that is less than a first thickness of the filament yarn in a relaxed state. Thereafter, the staple fiber covers the filament yarn component and confines the filament yarn component to a thickness which is less than the first thickness. The disclosures of U.S. Pat. No. 5,383,331 and co-pending Ser. No. 08/354,279, are hereby incorporated by reference.
Murata Machinery, Ltd. of Kyoto, Japan manufactures and sells a "high-speed type murata jet spinner" through Muratech of America Inc., 2120 I85 South, Charlotte, N.C. 28266. The Murata jet spinner can be utililzed to combine a core with an outer wrapping of fibers. However, with any of the known air-jet spinners it has been impossible to achieve a tight enough wrapping of fibers around a core to prevent slippage or pulling in the final yarn. The Murata jet-spinner (MJS) machine includes an MJS splicer which has been used to automatically remove an impurity or imperfection (known in the art as a slub) from the combined, spun yarn. Hereinafter, Applicants will refer to the slub as an imperfection, it being understood that this term is to be construed broadly and should include impurities as well as breaks in the yarn. A single splicer has been used to service a number of spinners, which are arranged in a parallel manner. The splicer travels back and forth in front of the row of spinners and automatically stops in front of the spinner where it is needed. Upon the detection, by a sensor, of a slub of a predetermined magnitude or greater, the MJS splicer is summoned to the station. Simultaneously, the feeding of the core and outer wrapper of fibers is stopped. Upon arrival, the splicer cuts the spun, combined yarn in the area between the last nip roll and the take-up roll and removes a predetermined amount of the spun yarn from the take-up package as well as a predetermined amount from upstream of the imperfection. The splicer then splices the yarn from the take-up package with the yarn from the jet-spinners. Accordingly, the MJS splicer automatically removes a slub from the spun, combined yarn, and splices the remaining yarn ends back together. However, Applicant's have discovered that the automated MJS splicer will not work automatically when the core yarn is tensioned as is the case in applicant's commonly owned U.S. Pat. No. 5,383,331 and Ser. No. 08/354,279. Accordingly, upon the detection of a slub in an installation based on the '331 patent and '279 application configuration, the spun combined yarn must be manually fed into the MJS splicer, to overcome the tensile force on the core. Thereafter the imperfection is removed in a conventional manner.
Thus, there is a need in the art to permit an automatic removal of an imperfection from spun, combined yarn, where the core yarn is under tension.